Abstract: Ion intensities measured by an ADC detector subsystem are filtered using equivalent TDC event realizations. In one embodiment, an intensity measurement is received for at least one ion made by an ADC detector subsystem for each of m extractions of an ion beam, producing m intensities for the ion. Equivalent TDC event realizations are received for the ion for each intensity of the m intensities, producing m equivalent TDC event realizations. A filtered intensity for the ion is calculated that is a combination of the m intensities and the m event realizations. In another embodiment, for the ion, an equivalent TDC event realization is accumulated for ion events up to a threshold count of event realizations, N, and the ADC intensities are accumulated for all remaining ion events. A filtered intensity for the ion is calculated that is a combination of the equivalent TDC event realization and the ADC intensities.

Abstract: A precursor ion transmission window is moved in overlapping steps across a precursor ion mass range. The precursor ions transmitted at each overlapping step by the mass filter are fragmented or transmitted. Intensities or counts are detected for each of the one or more resulting product ions or precursor ions for each overlapping window that form mass spectrum data for each overlapping window. Each unique product ion detected is encoded in real-time during data acquisition. This encoding includes sums of counts or intensities of each unique ion detected the overlapping windows and positions of the windows associated with each sum. The encoding for each unique ion is stored in a memory device rather than the mass spectral data. A deblurring algorithm or numerical method is used to determine a precursor ion of each unique ion from the encoded data.

Abstract: A precursor ion transmission window is moved in overlapping steps across a precursor ion mass range. The precursor ions transmitted at each overlapping step by the mass filter are fragmented or transmitted. Intensities or counts are detected for each of the one or more resulting product ions or precursor ions for each overlapping window that form mass spectrum data for each overlapping window. Each unique product ion detected is encoded in real-time during data acquisition. This encoding includes sums of counts or intensities of each unique ion detected the overlapping windows and positions of the windows associated with each sum. The encoding for each unique ion is stored in a memory device rather than the mass spectral data. A deblurring algorithm or numerical method is used to determine a precursor ion of each unique ion from the encoded data.

Abstract: A mass spectrometer that includes an MCP detector selects and analyzes a calibrant compound that has a first isotope and a second isotope with a known abundance ratio. The mass spectrometer measures the intensity of the first isotope that produces multiple-ion strikes at the MCP detector and the intensity of the second isotope that produces single-ion strikes at the MCP detector while the bias voltage of the MCP detector is stepped through a sequence of one or more different voltages. At each step, the ratio of the measured intensities is compared to the known abundance ratio for the two isotopes. When the measured ratio is within a predetermined threshold of the known abundance ratio, an optimum voltage for the MCP detector is calculated using one or more measured ratios calculated for voltages of the sequence of voltages.

Abstract: An uncertainty weighted average of the equalized amounts of two or more quantifier ions is calculated from a quantitation experiment itself. n known i ions of a compound are mass analyzed over time in each of m different samples, producing n XIC peaks for each of the m samples. A reference ion j is selected that is a j ion of the n i ions or a hypothetical ion j. A ratio r(j,i) of a peak area of the j ion to a peak area of each ion of the n i ions is calculated for each of the m samples, producing m r(j,i) ratios for each of the n i ions. An expected ratio rq(j,i) is calculated for each ion of the n i ions from the m r(j,i) ratios for each of the n i ions. For each sample, the uncertainty weighted average is calculated using rq(j,i).

Abstract: Each of one or more unknown compounds are separated from a sample over a separation time period. Separated compounds are ionized, producing one or more compound precursor ions for each of the unknown compounds and a plurality of background precursor ions. A precursor ion mass spectrum is measured for the combined compound and background precursor ions at each time step of a plurality of time steps spread across the separation time period, producing a plurality of precursor ion mass spectra. One or more background precursor ions are selected from the plurality of precursor ion mass spectra that have a resolving power in a range below a threshold expected resolving power. A separation time is detected for an unknown compound when a decrease in an intensity measurement of the selected background precursor ions over a time period exceeds a threshold decrease in intensity with respect to time.

Abstract: Dynamic skimmer pulsing and dynamic equilibration times are used for MS and MS/MS scans. A target percentage transmission of the ion beam is calculated based on a previous percentage transmission and a previous TIC or a previous highest intensity of a previous cycle time. An equilibration time is calculated based on the current percentage transmission and the target percentage transmission. A skimmer of a tandem mass spectrometer is controlled to attenuate the ion beam to the target percentage transmission to prevent saturation of a detector of the tandem mass spectrometer and to increase the dynamic range of the tandem mass spectrometer. The tandem mass spectrometer is controlled to perform an MS scan or an MS/MS scan after the calculated equilibration time to reduce the cycle time.

Abstract: Intensity measurements made by electron multiplier and image-charge detectors are proportional to charge state. These intensities are used to separate detected ions into different data sets and create mass spectra from the different data sets. Ion measurements are separated by charge state using (i) a single electron multiplier detector, (ii) a single image-charge detector, or (iii) multiple electron multiplier ADC detectors. Using (i), the intensity of a peak calculated from each measured pulse is compared to predetermined intensity ranges and each peak is stored in a corresponding data set. Using (ii), each measured transient time-domain signal is converted to frequency-domain peaks, the intensity of each frequency-domain peak is compared to predetermined intensity ranges, and each peak is stored in a corresponding data set. Using (iii), each detector is adapted to measure a predetermined intensity range and store calculated peaks from the measured pulses in corresponding data sets.

Abstract: Dynamic skimmer pulsing and dynamic equilibration times are used for MS and MS/MS scans. A target percentage transmission of the ion beam is calculated based on a previous percentage transmission and a previous TIC or a previous highest intensity of a previous cycle time. An equilibration time is calculated based on the current percentage transmission and the target percentage transmission. A skimmer of a tandem mass spectrometer is controlled to attenuate the ion beam to the target percentage transmission to prevent saturation of a detector of the tandem mass spectrometer and to increase the dynamic range of the tandem mass spectrometer. The tandem mass spectrometer is controlled to perform an MS scan or an MS/MS scan after the calculated equilibration time to reduce the cycle time.

Abstract: The resolution of a TOF mass analyzer is maintained despite a loss of resolution in one or more channels of a multichannel ion detection system by selecting the highest resolution channels for qualitative analysis. Ion packets that impact a multichannel detector are converted into multiplied electrons and emitted from two or more segmented electrodes that correspond to impacts in different regions across a length of the detector. The electrons received by each electrode of the two or more segmented electrodes for each ion packet are converted into digital values in a channel of a multichannel digitizer, producing digital values for at least two or more channels. Qualitative information about the ion packets is calculated using digital values of a predetermined subset of one or more channels of the at least two or more channels known to provide the highest resolution.

Abstract: The resolution of a TOF mass analyzer is maintained despite a loss of resolution in one or more channels of a multichannel ion detection system by selecting the highest resolution channels for qualitative analysis. Ion packets that impact a multichannel detector are converted into multiplied electrons and emitted from two or more segmented electrodes that correspond to impacts in different regions across a length of the detector. The electrons received by each electrode of the two or more segmented electrodes for each ion packet are converted into digital values in a channel of a multichannel digitizer, producing digital values for at least two or more channels Qualitative information about the ion packets is calculated using digital values of a predetermined subset of one or more channels of the at least two or more channels known to provide the highest resolution.

Abstract: Each of one or more unknown compounds are separated from a sample over a separation time period. Separated compounds are ionized, producing one or more compound precursor ions for each of the unknown compounds and a plurality of background precursor ions. A precursor ion mass spectrum is measured for the combined compound and background precursor ions at each time step of a plurality of time steps spread across the separation time period, producing a plurality of precursor ion mass spectra. One or more background precursor ions are selected from the plurality of precursor ion mass spectra that have a resolving power in a range below a threshold expected resolving power. A separation time is detected for an unknown compound when a decrease in an intensity measurement of the selected background precursor ions over a time period exceeds a threshold decrease in intensity with respect to time.

Abstract: A precursor ion transmission window is moved in overlapping steps across a precursor ion mass range. The precursor ions transmitted at each overlapping step by the mass filter are fragmented or transmitted. Intensities or counts are detected for each of the one or more resulting product ions or precursor ions for each overlapping window that form mass spectrum data for each overlapping window. Each unique product ion detected is encoded in real-time during data acquisition. This encoding includes sums of counts or intensities of each unique ion detected the overlapping windows and positions of the windows associated with each sum. The encoding for each unique ion is stored in a memory device rather than the mass spectral data. A deblurring algorithm or numerical method is used to determine a precursor ion of each unique ion from the encoded data.

Abstract: Intensity measurements made by electron multiplier and image-charge detectors are proportional to charge state. These intensities are used to separate detected ions into different data sets and create mass spectra from the different data sets. Ion measurements are separated by charge state using (i) a single electron multiplier detector, (ii) a single image-charge detector, or (iii) multiple electron multiplier ADC detectors. Using (i), the intensity of a peak calculated from each measured pulse is compared to predetermined intensity ranges and each peak is stored in a corresponding data set. Using (ii), each measured transient time-domain signal is converted to frequency-domain peaks, the intensity of each frequency-domain peak is compared to predetermined intensity ranges, and each peak is stored in a corresponding data set. Using (iii), each detector is adapted to measure a predetermined intensity range and store calculated peaks from the measured pulses in corresponding data sets.

Abstract: Two-channel electrical and photo-electrical TOF ion detection systems are provided. These systems maintain the resolution and dynamic range advantages of four-channel systems but at a lower cost. Electrodes or light pipes are configured to direct electrons or photons produced by ion impacts into two separate channels. The first channel receives electrons or photons resulting from the inner or central part of the rectangular pattern of each ion impact. The second channel receives electrons or photons resulting from the two outer ends of the rectangular pattern of each ion impact. In a two-channel digitizer, the first channel and the second channel are independently calibrated to align the first digital value and the second digital value in time and account for the convex shape of the ion impacts of each ion packet and/or the curvature of a microchannel plate.

Abstract: Dynamic skimmer pulsing and dynamic equilibration times are used for MS and MS/MS scans. A target percentage transmission of the ion beam is calculated based on a previous percentage transmission and a previous TIC or a previous highest intensity of a previous cycle time. An equilibration time is calculated based on the current percentage transmission and the target percentage transmission. A skimmer of a tandem mass spectrometer is controlled to attenuate the ion beam to the target percentage transmission to prevent saturation of a detector of the tandem mass spectrometer and to increase the dynamic range of the tandem mass spectrometer. The tandem mass spectrometer is controlled to perform an MS scan or an MS/MS scan after the calculated equilibration time to reduce the cycle time.

Abstract: A system is disclosed for identifying a precursor ion of a product ion in a scanning DIA experiment. A precursor ion mass selection window is scanned across a precursor ion mass range of interest, producing a series of overlapping windows across the precursor ion mass range. Each overlapping window is fragmented and mass analyzed, producing a plurality of product ion spectra for the mass range. A product ion is selected from the spectra. Intensities for the selected product ion are retrieved for at least one scan across the mass range producing a trace of intensities versus precursor ion m/z. A matrix multiplication equation is created that describes how one or more precursor ions correspond to the trace for the selected product ion. The matrix multiplication equation is solved for one or more precursor ions corresponding to the selected product ion using a numerical method.

Abstract: Two-channel electrical and photo-electrical TOF ion detection systems are provided. These systems maintain the resolution and dynamic range advantages of four-channel systems but at a lower cost. Electrodes or light pipes are configured to direct electrons or photons produced by ion impacts into two separate channels. The first channel receives electrons or photons resulting from the inner or central part of the rectangular pattern of each ion impact. The second channel receives electrons or photons resulting from the two outer ends of the rectangular pattern of each ion impact. In a two-channel digitizer, the first channel and the second channel are independently calibrated to align the first digital value and the second digital value in time and account for the convex shape of the ion impacts of each ion packet and/or the curvature of a microchannel plate.

Abstract: A system is disclosed for identifying a precursor ion of a product ion in a scanning DIA experiment. A precursor ion mass selection window is scanned across a precursor ion mass range of interest, producing a series of overlapping windows across the precursor ion mass range. Each overlapping window is fragmented and mass analyzed, producing a plurality of product ion spectra for the mass range. A product ion is selected from the spectra. Intensities for the selected product ion are retrieved for at least one scan across the mass range producing a trace of intensities versus precursor ion m/z. A matrix multiplication equation is created that describes how one or more precursor ions correspond to the trace for the selected product ion. The matrix multiplication equation is solved for one or more precursor ions corresponding to the selected product ion using a numerical method.

Abstract: A sample is ionized using an ion source and the ion beam is received using a tandem mass spectrometer. An m/z range is divided into two or more precursor ion isolation windows. Two or more values for a fragmentation parameter are selected. A first value of the two or more values for the fragmentation parameter has a level that fragments a minimal amount of ions of the ion beam. The one or more additional values have increasingly aggressive levels that produce increasingly more fragmentation of the ions of the ion beam. For each precursor ion isolation window, the tandem mass spectrometer is instructed to perform a selection and fragmentation of the ion beam using the precursor ion isolation window and the first value and is instructed to perform one or more additional selections and fragmentations of the ion beam using the precursor ion isolation window and using the one or more additional values.